package com.demo.nio;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set;

/**   
* @Description: TODO(用一句话描述该文件做什么) 
* @author thomas_liu  
* @date 2018年4月26日 上午11:18:40 
* @version V1.0   
*/
public class MultiplexerTimeServer implements Runnable {

	
	private Selector selector;
	
	private ServerSocketChannel servChannel;
	
	private volatile boolean stop;
	
	/**
	 *初始化多路复用器，绑定监听端口 
	 * @param
	 */
	public MultiplexerTimeServer(int port){
		
		try {
			selector = Selector.open();
			servChannel = ServerSocketChannel.open();
			servChannel.configureBlocking(false);
			servChannel.socket().bind(new InetSocketAddress(port),1024);
			servChannel.register(selector, SelectionKey.OP_ACCEPT);
			System.out.println("The time server is start in port :" + port);
		} catch (IOException e) {
			e.printStackTrace();
			System.exit(1);
		}
		
	}
	
	public void stop(){
		this.stop = true;
	}
	
	public void run() {
		while(!stop){
			try {
				selector.select(1000);
				Set<SelectionKey> selectedKeys = selector.selectedKeys();
				Iterator<SelectionKey> it = selectedKeys.iterator();
				SelectionKey key = null;
				
				while(it.hasNext()){
					key = it.next();
					it.remove();
					try {
						handleInput(key);
					} catch (Exception e) {
						if(key != null){
							key.cancel();
							if(key.channel() != null){
								key.channel().close();
							}
						}
						
					}
				}
				
			} catch (Throwable t) {
				t.printStackTrace();
			}
		}

		if(selector != null){
			try {
				selector.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		
	}
	
	private void handleInput(SelectionKey key) throws IOException {
		
		if(key.isValid()){
			
			if(key.isAcceptable()){
				ServerSocketChannel ssc = (ServerSocketChannel) key.channel();
				SocketChannel sc = ssc.accept();
				sc.configureBlocking(false);
				sc.register(selector, SelectionKey.OP_READ);
			}
			
				if(key.isReadable()){
					SocketChannel sc = (SocketChannel) key.channel();
					ByteBuffer readBuffer = ByteBuffer.allocate(1024);
					int readBytes = sc.read(readBuffer);
					if(readBytes >0){
						readBuffer.flip();
						byte[] bytes = new byte[readBuffer.remaining()];
						readBuffer.get(bytes);
						String body = new String(bytes, "UTF-8");
						System.out.println("The time server receive order :" +body);
						String currentTime = "QUERY TIME ORDER".equalsIgnoreCase(body) ?new java.util.Date(System.currentTimeMillis()).toString():"BAD ORDER";
						doWrite(sc, currentTime);
					}else if(readBytes <0){
						//对端链路关闭
						key.cancel();
						sc.close();
					}
					
				}
			
		}
		
	}
	
	private void doWrite(SocketChannel channel, String response) throws IOException{
		if(response != null && response.trim().length() >0){
			byte[] bytes = response.getBytes();
			ByteBuffer writeBuffer = ByteBuffer.allocate(bytes.length);
			writeBuffer.put(bytes);
			writeBuffer.flip();
			channel.write(writeBuffer);
			
		}
	}
	
}
